P0A78-306
P112 HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0A78-306: Drive Motor "A" Inverter Performance
DTC P0A78-306 - Drive Motor "A" Inverter Performance
DESCRIPTION
The inverter converts the high-voltage direct current of the HV battery and the alternating current for the MG1/MG2. The inverter contains a three-phase bridge circuit, which consists of 6 power transistors each for the MG1 and the MG2, in order to convert the direct current and the three-phase alternating current. The HV control ECU controls the actuation of the power transistors.
The inverter transmits information that is necessary for effecting control, such as the amperage and voltage, to the HV control ECU.
The HV control ECU uses a voltage sensor, which has been built into the inverter, to detect the high voltage after boost control.
The inverter voltage sensor outputs a voltage that varies between 0 and 5 V in accordance with the changes in the high voltage. The higher the high voltage, the higher the output voltage, and the lower the high voltage, the lower the output voltage.
The HV control ECU monitors the inverter voltage and detects a malfunction.
The HV control ECU controls MG2 torque in accordance with the driving condition.
MONITOR DESCRIPTION
If the difference between the requested MG2 torque and the actual MG2 torque exceeds a predetermined value, the HV control ECU determines that there is malfunction in the execution or monitoring of the MG2 torque. Then, the HV control ECU illuminates the MIL and sets a DTC.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
COMPONENT OPERATING RANGE
INSPECTION PROCEDURE
CAUTION:
- Before inspecting the high-voltage system, take safety precautions to prevent electrical shocks, such as wearing insulated gloves and removing the service plug grip. After removing the service plug grip, put it in your pocket to prevent other technicians from reconnecting it while you are servicing the high-voltage system.
- After disconnecting the service plug grip, wait for at least 5 minutes before touching any of the high-voltage connectors or terminals.
HINT:
- At least 5 minutes are required to discharge the high-voltage condenser inside the inverter.
- When measuring insulation resistance using a megohmmeter, set the megohmmeter to 500 V.
PROCEDURE
1. READ OUTPUT DTC (HV ECU)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch ON (IG).
(c) Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.
(d) Check if DTCs are output.
Result:
DTC P0A78 (INF 306) and other DTCs are output
HINT: If any other codes besides P0A78 (INF 306) are output, perform troubleshooting for those DTCs first.
YES -- GO TO RELEVANT DTC CHART
NO -- Continue to next step.
2. CHECK HYBRID VEHICLE MOTOR ASSEMBLY
CAUTION: Wear insulated gloves before performing the following operation.
(a) Turn the power switch OFF.
(b) Remove the service plug grip Removal.
NOTE: Turning the power switch ON (READY) with the service plug grip removed could cause malfunction. Therefore, never turn the power switch ON (READY) in this state.
(c) Remove the inverter cover Removal.
(d) Check if the three-phase alternating current cable installation bolts on the hybrid vehicle motor are tightened to the specified torque.
Torque: 8.0 Nm (82 kgf-cm, 71 in-lbf)
NG -- TIGHTEN THEM TO SPECIFIED TORQUE
OK -- Continue to next step.
3. INSPECT HYBRID VEHICLE MOTOR ASSEMBLY
CAUTION: Wear insulated gloves before performing the following operation.
(a) Check that the service plug grip and inverter cover have been removed.
(b) Disconnect the three-phase alternating current cable for the hybrid vehicle motor from the inverter.
(c) Using a milliohm meter, measure the resistance between the three-phase alternating current cable terminals of the hybrid vehicle motor.
NOTE: If the motor temperature is too high, the resistance varies considerably, which hinders determining malfunction. Therefore, measure the resistance at a minimum 8 hours after the vehicle has been stopped.
Standard resistance:
- *: Apply the formula given below to correct the resistance.
- R20 = Rt / {1 + 0.00393 x (T - 20)}
- R20: Resistance converted to 68°F (20°C) (mOhms)
- Rt: Resistance between measured lines (mOhms)
- T: Ambient air temperature during measurement (°C)
(d) Calculate the difference between the maximum and minimum resistance between terminals U - V, V - W, and W - U.
Standard resistance:
Below 2 mOhms
(e) Using a megohmmeter set to 500 V, measure the insulation resistance between the three-phase alternating current cable terminals of the hybrid vehicle motor and the body ground.
NOTE: Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.
Standard resistance:
(f) Reconnect the three-phase alternating current cable for the hybrid vehicle motor.
(g) Reinstall the inverter cover Installation.
(h) Reinstall the service plug grip Installation.
NG -- REPLACE HYBRID VEHICLE MOTOR ASSEMBLY
OK -- REPLACE INVERTER WITH CONVERTER ASSEMBLY